This invention relates to a device and to a method of dissecting, grasping or cutting an object.
Many devices which are used commonly for grasping or cutting objects have two elements which can be moved towards one another and away from one another. The elements have surfaces which may be blunt or sharp so that an object positioned between them may be either grasped or cut when the elements are moved towards one another. Examples of such devices include tongs, tweezers, forceps, scissors, guillotines, and wire cutters. Such devices can also be adapted to dissect tissue, for example, by placing the elements of the device into or next to an object and then causing the elements to splay apart thereby dissecting the object.
The elements of such devices are generally rigid, and are moved relative to one another pivotally. The combined requirements that the elements be rigid and capable of pivotal movement can preclude their use in situations where there is a limited amount of space. Furthermore, it can be difficult to manipulate such devices remotely or at angles. These factors tend to make it difficult to use such devices within the body of an animal or human undergoing surgery, especially during less invasive surgical techniques, such as arthroscopy, endoscopy and laproscopy. During such surgery, it may be necessary to grasp and move tissue, for example, to expose an underlying site, to dissect tissue from surrounding tissue, and/or to cut diseased or damaged tissue.
In these less invasive surgical procedures, elongate housings have been developed to position the instrument or device into the body through a minimal incision. Example of such devices are disclosed in U.S. Pat. Nos. 2,670,519 to Recklitis, 2,114,695 to Anderson, 2,137,910 to Anderson, 3,404,677 to Springer, 3,491,747 to Robinson, 4,218,821 to Schneider, 4,423,729 to Gray, 4,612,708 to Hattori, 4,656,999 to Storz, 4,678,459 to Onik, 4,768,505 to Okada et al, European Patent No. 380,874 to Bencini and German Patents Nos. 1,266,446 to Fischer and 3,732,236 to Baumgart.
It has now been discovered that one or more elements of such grasping or cutting devices can be formed from a pseudoelastic material, preferably a pseudoelastic material, such as a shape memory alloy, which is capable of being greatly deformed without permanent deformation, to provide an improved device that can be more readily used in applications in which there is a limited amount of space. Furthermore, the device can be operated remotely or at angles more conveniently than previously used devices. The device, with appropriately configured edges can also be used to dissect tissue.
It has been proposed to make medical devices from pseudoelastic materials, but such prior art devices typically do not have elements which are splayed apart and then, preferably moved toward one another in the manner necessary in dissecting, grasping or cutting devices, such as forceps, scissors or the like. Further, prior art devices using pseudoelastic materials do not have elements which are near one another and then splay apart to separate or dissect tissue. Descriptions of medical devices made from pseudoelastic materials can be found in U.S. Pat. Nos. 4,616,656 to Nicholson et al, 4,665,906 to Jervis, 4,898,156 to Gatturna et al, 4,899,743 to Nicholson et al and 4,926,860 to Stice et al, the disclosures of which are incorporated herein by reference.